[0.16.27] Requesting from buffer chests gives chest supply priority

[Zanostra]

I stumbled on a logistic chest bug again.
The requester chests have this nice option where you can allow them to request from buffer chests. ( I love it )
But if one ( or more ) of the requester chests is allowed to receive an item from buffer chests, then the other requester chests do not get that item anymore at all.

requester chest.jpg (141.75 KiB) Viewed 3745 times

with or without mods, I can reproduce whenever I want with the setup in this screenshot.
both request iron, provided by the passive provider chests.
if both unchecked, both receive iron.
if both checked, both receive.
if 1 of them is checked, the other will not receive.
And I'm pretty sure that a requester should always receive from a passive provider.

[Loewchen]

Can not reproduce, post a save with the issue please.

[Zanostra]

when I tried again it didn't happen, I was very surprised, but I managed to do it again.
the requested amount needs to be more then the system can provide in.
a vanilla save file in the attachment.

[Rseding91]

Thanks for the report. This is working correctly:

The way you've set up the belts the items trickle into the provider chests and the requester chest requesting from buffers is never satisfied.

Each time items are added to the provider chest a robot is sent out that same tick or next to move them. That consumes all of the "supply" of plates and the game stops trying to dispatch robots to requester chests asking for iron that tick.

If you have > 1 robots worth of iron in a provider chest the game will send 1 robots worth to the left chest then the rest up to 1 robots worth to the right chest each tick.

[Zanostra]

so if I understand this correctly, they should be almost evenly divided when all of the materials get in at the same time?
because 1 robot carrying ( ~6 ) plates goes to the left one, and then the second goes to the right one until all is dispatched?

After you post I tried this, ( by using the uploaded savegame )
I removed all of the inserters, and took all plates in player inventory ( 500 metal )
both chests still requesting the 500 plates with one of them still checked the buffer chest option and the other not.
then I put all the 500 plates at once in one of the providers, so in 1 tic all 500 were present to be divided.
and still all of the plates went to the checked box chest.

I took the plates again and set both requests to 400,
put the 500 plates in a provider, again at once,
and the checked box chest got 400 and the other one the remaining 100.

so I still think the checked box chest gets priority until his demand is fully met, even if there is more than one robot cargo load available and enough robots idle to receive the orders.

EDIT*
I updated the save with some combinator logic so that the requester chests only make their requests when all robots and all plates are available at the same tic.
so you don't have to change anything anymore after opening the save.

[Szpak]

req bug.jpg (197.87 KiB) Viewed 3482 times

I hope it is a bug not a feature. Requester with 'request from buffer..' have priority over other requesters. If a demand is greater that current stock, requesters with this option enabled will be satisfied first.

[Rseding91]

req bug.jpg

I hope it is a bug not a feature. Requester with 'request from buffer..' have priority over other requesters. If a demand is greater that current stock, requesters with this option enabled will be satisfied first.

that's working as intended.

[Szpak]

that's working as intended.

Well in this case, it would be great if a reqester had another option: Request ONLY from buffer chest.
It would solve not only this problem but also a logistic loops in some cases.

[Progman]

req bug.jpg

I hope it is a bug not a feature. Requester with 'request from buffer..' have priority over other requesters. If a demand is greater that current stock, requesters with this option enabled will be satisfied first.

that's working as intended.

I ran in the same situation as well and stumble on this thread.

Can you explain the logic why there is a priority for a requester chest with the "Request from buffer chests" flag set when there aren't any buffer chests (only normal passive provider chests)?